In the BOSE headunit in my Avalanche they have found the audio inputs into those radios from auxilary CD changers or the XM radio inputs.

You may want to look for a similar route. The big issue for the GM radios is that the radios are not programmed to recognize the port if the radio wasn't connected to an external changer or satellite and required reprogramming. I can do this now in my Avalanche by switching to an XM radio station. Splice the audio in and away I go, Apparently there is an auxiliary option also but with this easy solution no one on the avalanche forum bothered trying to figure it out. It seemed to be tied to the external CD changer though.

Comment

In the BOSE headunit in my Avalanche they have found the audio inputs into those radios from auxilary CD changers or the XM radio inputs.

You may want to look for a similar route. The big issue for the GM radios is that the radios are not programmed to recognize the port if the radio wasn't connected to an external changer or satellite and required reprogramming. I can do this now in my Avalanche by switching to an XM radio station. Splice the audio in and away I go, Apparently there is an auxiliary option also but with this easy solution no one on the avalanche forum bothered trying to figure it out. It seemed to be tied to the external CD changer though.

Worse comes to worse, I'll have to figure out what kind of signal the CD changer would send to the headunit as an "on" signal, and reproduce that with a microcontroller/555 timer. Then I can send my audio through the external "PIE" connector.

I'm going to take out my factory headunit and take it apart. I'll let you guys know what I come up with.

-Electrical Engineering Student.

Comment

This is your easiest option if you MUST retain the factory radio... http://www.isimplesolutions.com/
they have vehicle specific or you can get the antenna interruption kit that works for all vehicles.. it simply interupts the antenna connection directly behind the back of your radio and you tune it to a specified frequency.. works a lot better then the FM MODS..

But honestly your best bet is to just replace the radio.. it can be done for less than a 100.. and will sound much better than all of the other options..

Comment

Did you make any progress on this? I've had some friends ask me similar questions about adding in an Aux input as opposed to CDs or tapes. Speculation: if you crack the unit open, and being EE, you could find the CDs player DAC, look up the part number, follow the traces, interrupt them, put in a smaller mixer circuit or toggle for an auxiliary audio input. Holy commas batman.

Get fancy! don't use a switch, use a 3.5mm jack with a switch built in to interrupt the CD players audio feed. And don't stop there, tie into whatever mechanism senses there is a CD for auto aux input switching! (might be a problem if it doesn't detect a disc spinning up and tries to eject it/forces itself into a loop)